Field of the Invention
The present invention relates to correction of a distortion of a projection image in a projection-type image display system.
Description of the Related Art
A technique for correcting a distortion of a projection image projected by a projector by capturing an image of the projection image and calculating a distortion correction parameter from the captured image is available.
Japanese Patent No. 3996610 discloses that a distortion is corrected by reducing the dimensions of a projection image projected by a projector in the case where the projection image is larger than a screen. More specifically, the projector projects images obtained by reducing dimensions of the full-size projection image to 75% and 50%, and captures images of the individual projection images. The projector then calculates the position of the full-size projection image projected by the projector and corrects a distortion of the full-size projection image.
However, a distortion of a projection image may not be appropriately corrected depending on the dimensions of the projection image.
For example, in an example described in Japanese Patent No. 3996610, in the case where a range occupied by the projection image is not identifiable using a projection image obtained by reducing the dimensions of the full-size projection image to 75%, a distortion of the projection image may not be appropriately corrected.